This invention generally relates to diagnosing fault conditions associated with powering electrical loads.
A variety of electrically powered components are typically provided on motorized vehicles. Examples includes electric motors that are used for actuating various vehicle components. Other example loads include motor brakes. It is not uncommon to experience difficulty in powering such loads. While recognizing when a fault condition occurs is not always difficult, there has not been a way of accurately determining the nature or cause of the fault condition.
There is a need for being able to determine the type of fault condition present in a particular circumstance. For example, it is useful to determine whether a fault condition is associated with a short across the load or a short to ground from one side of the load, for example. Prior to this invention there has not been an effective and efficient way to determine the cause or nature of a fault condition.
In general terms, this invention is a method and system for diagnosing a fault condition associated with powering an electrical load where the electrical load includes a high side driver portion and a low side driver portion.
In a method of this invention, the high side driver portion and low side driver portion are selectively powered in a plurality of combinations. Example combinations include no power to both driver portions, power only to the high side driver portion and power to both of the driver portions.
During each of the selected powering combinations, at least one voltage associated with the high side driver portion is sampled. At least one voltage associated with the low side driver portion is also sampled during each of the selected combinations. The sampled voltages provide information that is used to diagnose the type of fault present under given circumstances.